Apparatus, and associated method, for allocating channels in a radio communication system responsive to mobile station movement

ABSTRACT

Apparatus, and an associated method, for allocating channels within a cell of a cellular communication system. Allocations are made by an allocator based upon determinations made by a determiner of the likelihood of movement of the mobile station. Determinations made by the determiner are made responsive to analyses of indicia of prior movement behavior of the mobile station stored at a home location register associated with the mobile station. Channel reuse is effectuated if the mobile station is determined to be stationary or moving at a speed less than a selected threshold. Otherwise, uniquely-assigned channels are allocated to the mobile station.

The present invention relates generally to a manner by which to reusechannels within a cell of a cellular communication system. Moreparticularly, the present invention relates to apparatus, and anassociated method, by which selectably to reuse channels at selectedzones within a cell, responsive to statistical indication of movement ofa mobile station.

When a mobile station to which a channel is to be allocated appearsunlikely to be moving at a speed beyond a selected threshold, thechannel allocated thereto is selected pursuant to a channel reusescheme. Otherwise, a uniquely-assigned channel is allocated forcommunications with the mobile station. Increased radio channel capacityis permitted as channels are selectably reused within a cell. Channelsare reused only upon determination that the reuse shall not interferewith ongoing communications elsewhere in the cell. The increasedcapacity is provided, therefore, without increase in channelinterference.

BACKGROUND OF THE INVENTION

Operation of a communication system provides for the communication ofdata between two or more spaced-apart locations. Communication stationspositioned at the separate locations are connected by way of acommunication channel upon which the data is communicated therebetween.A communication system, at which the data is sourced, forms a sendingstation that operates to send the data upon the communication channel.And, a communication station, positioned at the second location forms areceiving station operable to detect, and operate upon, the datacommunicated upon the communication channel by the sending station.

A radio communication system is a type of communication system in whichthe communication channel interconnecting the communication stations isformed upon a radio link. Because a radio link is utilized upon which todefine the communication channels used to communicate data between thecommunication stations, a wireline connection is not required to beformed between the communication stations.

Communications by way of a radio communication system are thereforeadvantageous when the use of a wireline connection would be inconvenientor impractical. Radio communication systems are also generally moreeconomical to install as the infrastructure costs associated with aradio communication system are generally less than the correspondinginfrastructure costs of a wireline communication system.

A cellular communication system is exemplary of a radio communicationsystem. A cellular communication system provides for the effectuation oftelephonic communications by way of radio channels. Cellularcommunication systems have been installed throughout significant partsof the populated portions of the world. Various cellular communicationstandards have been promulgated, setting forth the operationalparameters of different types of cellular communication systems.

Typically, a cellular communication system includes a fixed networkinfrastructure that is installed throughout the geographical area thatis to be encompassed by the communication system. The fixed networkinfrastructure includes fixed-site, base transceiver stations. Thefixed-site base transceiver stations are positioned at space-apartlocations, and each base transceiver station defines an area, referredto as a cell, from which the cellular communication system derives itsname. And, the fixed network infrastructure is coupled to a corenetwork, such as a packet data backbone, or a public-switched telephonicnetwork. Communication devices, such as computer servers, telephonicstations, etc., are connected to, or form portions of, the core network.

Mobile stations are utilized through which to communicate with the basetransceiver stations. Mobile stations are formed of radio transceivers,usually of dimensions that permit their carriage by users. Use of thecellular communication system is permitted, typically, pursuant to aservice subscription. And, users referred to as subscribers, communicateby way of the cellular communication system through utilization of themobile stations.

Cellular communication systems are used extensively to communicatetelephonically. Communication of voice, and other, data is popularlyeffectuated by way of cellular communication systems. Usage levels ofmany cellular communication systems have, at times, approached maximumsystem capacity. System capacity is sometimes constrained by thebandwidth allocated to the communication system. When communicationcapacity is met, additional communications in the communication systemare not permitted until ongoing communication sessions are terminated.For CDMA system, additional communications may permitted. However, thereceived signal for all the mobile calls will have a low voice/dataqualities. As new types of communication services are being madeavailable for effectuation by way of cellular communication systems,capacity problems are likely to continue.

Efforts, therefore, are made to find manners by which to increase thecommunication capacity of cellular communication systems. Many mannersby which to increase the communication capacity of the communicationsystem also cause an increase in co-channel interference. Cellsectorization is exemplary of a manner sometimes used by which toattempt to increase communication capacity in a cellular system. Throughuse of a cell sectorization technique, system capacity can be increasedwithout a corresponding increase in a co-channel interference ratio.But, use of a cell sectorization technique decreases trunking efficiencyand increases handoff loading due to increased numbers of handoffs.

Cell-splitting techniques are also sometimes used to increasecommunication capacity in a cellular communication system. Channelcapacity is increased by reducing the size of the cell. But,cell-splitting techniques also increase the handoff loading, therebyburdening the system link/switch capacity at the MSC (mobile switchingcenter) thereof.

Because of the increased loading, as well as other difficulties, use ofcell sectorization or cell splitting techniques by which to increasesystem capacity is somewhat limited.

Transmitter beam forming techniques are also sometimes used to increasethe co-channel interference ratio (CCIR). But, beam forming typicallyrequires the use of sophisticated, phase-array antennas and also the useof direction-of-arrival (DOA) algorithms. And, interference cancellationand multi-user detection techniques are also sometimes utilized. But,these techniques require complex computations to be carried out toperform the functions of such techniques.

Existing techniques by which to increase the communication capacity of acellular communication system, therefore, suffer from variousdisadvantages due to, e.g., variously increased handoff loading orincreased computational complexity, an improved manner by which toincrease the capacity of a cellular communication system would thereforebe advantageous.

It is in light of this background information related to communicationsin a cellular, or other, radio communication system that the significantimprovements of the present invention have evolved.

SUMMARY OF THE INVENTION

The present invention, accordingly, advantageously provides apparatus,and an associated method, by which to reuse channels within a cell of acellular communication system.

Through operation of an embodiment of the present invention, a manner isprovided by which selectively to reuse channels at selected zones withina cell responsive to statistical indications of movement of a mobilestatement.

If a mobile station to which a channel is to be allocated appearsunlikely to be moving at a speed greater than a selected threshold, thechannel that is allocated to the mobile station is selected pursuant toa code reuse scheme. If, instead, the mobile station is determined to bemoving at a speed greater than the selected threshold, auniquely-assigned channel is instead allocated for communication withthe mobile station.

Operation of an embodiment of the present invention permits the radiochannel capacity in the cell to be increased as channels are selectablyreused within the cell. Channels are reused only upon determination thatthe reuse shall not increase the co-channel interference ratio, i.e.,not interfere with ongoing communications elsewhere in the cell. Theincreased capacity is provided, therefore, without increase in channelinterference. And, increase in the capacity is provided also withoutincrease in handoff loading within the cell as the number of handoffsrequired to be performed within the cell remains unchanged.

Therefore, through operation of an embodiment of the present invention,the number of radio channels available upon which to be allocated foreffectuation of a communication session within a cell is increasedwithout increasing the channel interference ratio. And, no handoffsignaling increase, at the base station controller or mobile switchingcenter, is required in the cell, i.e., reducing link/switch signalingburden or increase link/switch capacity. Therefore, the overallcapacity, i.e., the radio capacity, the link capacity, and the switchcapacity, are significantly improved. Thereby, the capacity of thecommunication system is permitted to be increased such as in amountsgreat enough to permit the sending of high-speed data by way of multipleradio channels as well as to permit early-reservation of channels forcommunications with mobile stations for which the cell forms a targetcell.

In one aspect of the present invention, a cell is divided into aplurality of zones. Each zone is defined by a zone antenna. Separatezone antennas are positioned at spaced-locations within the cell. And,each zone antenna is coupled to a base transceiver station that definesthe cell. Mobile stations generate reverse-link signals that aredetected by individual ones of the zone antennas. And, forward-linksignals are generated by the zone antennas, for communication to themobile stations. Macro diversity combining is used on the reverse-linkcommunications. And, forward-link signals, such as pilot signalsgenerated in a CDMA system, are transmitted by each of the zoneantennas, in synchronization, due to the common coupling with the basetransceiver station. Because of the positioning of the zone antennas atthe spaced locations throughout the cell, reverse- and forward-linksignals can be communicated at reduced power levels, generally, relativeto the power levels required to communicate corresponding signals in asystem in which the signals must be communicated directly with the basetransceiver station.

In another aspect of the present invention, the moving behavior of amobile station is determined, at least on a statistical basis. If themobile station is moving, the mobile station shall successivelycommunicate with successive zone antennas. And, if the mobile station isnear stationary, the mobile station communicates successively with asingle zone antenna. When the mobile station is not moving, or moving ata speed less than a selected threshold, the channel allocated to themobile station for communication thereon is selected pursuant to achannel reuse scheme. If, conversely, the mobile station is determinedto be moving at a speed in excess of a selected threshold, the channelallocated to the mobile station forms a uniquely-assigned channel withinthe cell.

In another aspect of the present invention, indicia associated with themoving behavior of the mobile station is stored at a home locationregister (HLR) associated with the mobile station. The indicia define acharacteristic profile of the mobile station. Indicia associated withthe mobile station is generated, for instance, during registrationprocedures and during selected update intervals thereafter. When asubsequent request for allocation of a channel to the mobile station isgenerated, such as when a mobile-originated call is initiated or when amobile-terminated call is originated, the moving behavior of the mobilestation is accessed and analyzed to determine whether to allocate achannel to the mobile station pursuant to a reuse scheme or to allocatea uniquely-assigned channel to the mobile station.

In another aspect of the present invention, determinations of in whatmanner to allocate a channel to the mobile station is made on aprobabilistic basis. That is to say, a probability of subsequentmovement of the mobile station is determined, based upon historicalindicia stored at the location register of past movement of the mobilestation.

In one implementation, a mobile-location assisted code reuse schemewithin a cell defined in a CDMA (code-division multiple-access) cellularcommunication system is provided. Channels in the system are defined bycodes by which data is encoded prior to its communication betweencommunication stations of the system. And, the cell is divided into aplurality of zones, each zone defined by a zone antenna that is coupledto a base transceiver station. Moving behavior associated with themobile station is generated and indicia thereof is stored at a homelocation register associated with the mobile station. When a channel isrequested to be allocated to the mobile station, determination is made,on a statistical basis, whether the mobile station is likely to bemoving at a speed in excess of a selected threshold. If so, the mobilestation is assigned a unique code, unique throughout the cell, by whichto encode data pursuant to a communication session. If, conversely, adetermination is made, on a statistical basis, that the mobile stationshall be unlikely to be traveling at a speed in excess of the selectedthreshold, the code assigned to the mobile station is selected pursuantto a code reuse scheme within the cell.

Thereby, channel capacity within the cell is increased as channels areselectably reused within the cell. If the mobile station is determinednot to be moving, channel reuse is permitted. But, if a mobile stationis determined to be likely to be moving beyond a selected speed, thechannel allocated to the mobile station is uniquely-assigned, therebybetter to ensure that co-channel interference does not occur.

In these and other aspects, therefore, apparatus, and an associatedmethod, is provided for a radio communication system. The radiocommunication system has a mobile station selectably moveable throughoutan area defining a cell. The cell is divided into a first zone and atleast a second zone. A channel is selectably assigned for communicationswith the mobile station. A position and movement determiner is coupledto receive indicia associated with positioning and movement of themobile station. The position and movement determiner determines aposition of the mobile station and a statistical indication of a speed,if any, at which the mobile station is moving. A channel allocator iscoupled to the position and movement determiner. The channel allocatorselectably assigns the channel for the communications with the mobilestation. Channel assignment made by the channel allocator areresponsive, at least in part, to the position and speed of the mobilestation.

A more complete appreciation of the present invention and the scopethereof can be obtained from the accompanying drawings that are brieflysummarized below, the following descriptions of the presently-preferredembodiments of the invention, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a functional block diagram of a portion of a cellularcommunication system in which an embodiment of the present invention isimplemented.

FIG. 2 illustrates a functional block diagram representative of a mannerby which selectably to connect zone antennas forming a portion of thecellular communication system shown in FIG. 1 on the forward and reverselinks to effectuate communications thereon.

FIG. 3 illustrates a process diagram representing operation of anembodiment of the present invention.

FIG. 4 illustrates an exemplary table generated during operation of anembodiment of the present invention showing an exemplary channel reusescheme.

FIG. 5 illustrates another process diagram, also representative ofoperation of an embodiment of the present invention.

DETAILED DESCRIPTION

Referring first to FIG. 1, a portion of a radio communication system,shown generally at 10, provides for radio communications with a mobilestation 12. In the exemplary implementation, the communication system 10forms a cellular communication system operable, generally, pursuant to aCDMA (code-division, multiple-access) communication protocol, such asthat defined in the CDMA 2000 or W-CDMA operational specification. Theteachings of the present invention are, however, also implementable inother types of cellular and other radio, communication systems thatdefine channels in manners other than by using unique codes. Forinstance, the teachings of the present invention are analogously alsoimplementable in communication systems that utilize TDMA (time-division,multiple-access) communication schemes, such as the system defined inthe GS7 (general system for mobile communications) operationalspecification. Accordingly, while the following description shalldescribe operation of an embodiment of the present invention withrespect to its implementation in a CDMA communication system, thepresent invention is analogously also operable in other types ofcommunication systems.

Here, a single cell 14 of the cellular communication system isrepresented. The cell 14 is defined by a base transceiver station (BTS)16 that forms a portion of the network part of the communication system.The cell 14 is represented in a hexagonal configuration. In an actualimplementation, the configuration, and size, of the cell might welldiffer with that shown. And, the system typically includes a largenumber of cells, each defined by a separate base transceiver station.

The cell 14 is divided into a plurality of smaller-sized zones 18. Eachof the zones is defined by a zone antenna 22. The zone antennas are eachconnected, or otherwise coupled to, the base transceiver station. Datacommunicated between the mobile station and the base transceiver stationis transduced by zone antennas positioned in proximity to the mobilestation. Some of the zones are identified in the figure by alphabeticalcharacters A, B, C, D, E, F, G, H, I and J. Such alphabetical charactersalso indicate code groupings, as shall be described herein below.

The zone antennas 22 are each coupled to the base transceiver station byway of a busline 24. The busline extends to functional elements of thebase transceiver station. Here, the functional elements of the basetransceiver station are represented at the block 26, here shown forpurposes of illustration, separate from the base transceiver station butconnected to the busline 24. The functions performed by the elementswithin the block 26 are performed by the base transceiver station 16 orelsewhere.

The base transceiver station 16 forms part of the access network of thecommunication system. Additional elements of the access network arerepresented at the additional access network entities block 28.Additional access network entities include, for instance, a radionetwork controller and a gateway device. The access network, in turn, iscoupled to a core network 32. Correspondent entities, such as acorrespondent node 34, are coupled to the core network. Communicationsare effectible between the correspondent node 34 and a mobile station,such as the mobile station 12, through the formation of a communicationpath through the core network, the access network 28 (and basetransceiver station 16 thereof), and upon radio channels defined upon aradio link extending between an appropriate zone antenna 22 and themobile station.

As the mobile station is permitted mobility, the mobile station mightmove throughout the cell, as well as move between cells of thecommunication system. Through operation of an embodiment of the presentinvention, a manner is provided by which selectively to allocatechannels to the mobile station for communications therewith. If themobile station is stationary, or moving at a speed less than a selectedthreshold, the channel allocated to the mobile station is selectedpursuant to a channel reuse scheme. If, conversely, the mobile stationis moving at a speed greater than the selected threshold, the channelallocated to the mobile station is not used elsewhere in the cell but,instead, is a uniquely-assigned channel. In the CDMA system of theexemplary implementation, the channels are defined by spreading codes,and the channel is allocated to the mobile station comprise such codes.

The mobile station 12 is associated with a home location register (HLR)38. The location register 38 operates, in conventional manner, tomaintain a database registry associated, amongst other things, withindications of the cell or region within which the mobile station islocated. The home location register here also includes a mobile stationmoving behavior indicia database 42 that forms a portion of anembodiment of the present invention. During operation of thecommunication system, moving behavior indicia is provided to the homelocation register and stored at the database 42 thereof. The movingbehavior indicia includes, for instance, position and time informationassociated with the mobile station. Such indicia is utilized by theapparatus 26 to obtain a statistical-based, probability of subsequentmovement of the mobile station. Responsive to the determinations, thechannel allocated to the mobile station is either a reused channel or auniquely-assigned channel.

The apparatus 26 is here shown to include a position and movementdeterminer 46 and a channel allocator 48. The elements 46 and 48 arefunctional entities and are implemented in any desired manner. In theexemplary implementation, the elements are implemented by algorithmsexecutable by a processing device.

When a channel allocation request is made to allocate a channel forcommunications with the mobile station, the position and movementdeterminer accesses data stored at the mobile station moving behaviorand indicia database 42. The position and movement of the mobile stationis determined therefrom. And, a determination is made whether the mobilestation is moving at a speed greater than the selected threshold.

The channel allocator 48 operates responsive to determinations made bythe determiner 46. The determiner and allocator, in the exemplaryimplementation, define a code reuse algorithm, here for a CDMA system,based upon knowledge of the moving behavior of the mobile station.During operation of the communication system at the cell 14, all of thezones 18 are co-located with a main base transceiver station 16 at thecell. Pilot signals generated during operation of the communicationsystem are generated by the base transceiver station 16 and every zoneshares the same radio equipment installed at the base transceiverstation. All of the signals transmitted by way of the zone antennas thatdefine respective ones of the zones and the base transceiver station aresynchronized. When a mobile station is positioned within a particularzone 18, signals transmitted upon forward links to the mobile stationare transduced only by the zone antenna defining the zone at which themobile station is located. Conversely, when the mobile station generatessignals communicated on the reverse-link channels, a macro diversitycombining scheme is utilized to detect the reverse-link signals at,potentially, more than one of the zone antennas. That is to say, zoneantennas at a zone cluster about the mobile station detect thereverse-link signals. Therefore, macro diversity combining is achievablewithin the zone cluster of the cell and another zone, positioned awayfrom the zone cluster in the cell, while reusing the same orthogonalcode, or other channel.

The code reuse incentive depends upon the probability of the mobilestation being stationary and the co-channel interference between thecode reuse zones. A zone area encompasses any of various designatedareas, such as areas of less than one hundred meter diameters or areasof as great as, or even greater than, a couple of hundred meters.

The indicia stored at the database 42 is statistically updated andrecorded, e.g., twenty-four hour paging-zone records, are maintained.When a mobile-originated or a mobile-terminated call is placed and achannel is to be allocated to the mobile station, the characteristicprofile of the mobile station, identified by the moving behaviorindicia, is accessed. Determination is made, statistically, whether themobile station is stationary or is moving. If, for instance, adetermination is made that the mobile station exhibits a ninety-ninepercent probability that the mobile station has been stationary before,and subsequent to a time window centered at the time instance, themobile station is determined to be statistically stationary. And, anorthogonal code, used elsewhere by another stationary mobile station,can be reused.

-   -   A channel formed upon a radio link with a mobile station is,        typically, a Rayleigh fading channel and the long-term fading        characteristics of the channel are assumed to be of a log-normal        distribution, Pr, that the receive signal level shall exceed a        certain threshold value γ in dBm is defined as follows:

$\begin{matrix}{{{Prob}\lbrack {{P(d)} > \gamma} \rbrack} = {Q( \frac{\gamma - {E\lbrack {P(d)} \rbrack}}{\sigma} )}} & (3) \\{and} & \; \\{{E\lbrack {P(d)} \rbrack} = {{P( d_{0} )} + {10 \cdot n \cdot {\log( \frac{d}{d_{0}} )}}}} & (4)\end{matrix}$Wherein:

-   -   P(d) is the receive signal power in dBm;    -   Q is the probability-theory Q function;    -   σ is the standard deviation of the receive signal in dB;    -   E[P(d)] is the mean received power in dBm; d₀ is the reference        distance; and nis the path loss exponent.        The ratio of probability channel interference measurement is        based upon:

$\begin{matrix}{{{The}\mspace{14mu}{ratio}\mspace{14mu}{of}\mspace{14mu}{probability}\mspace{14mu}{of}\mspace{14mu}\frac{C}{I}} = \frac{{Prob}\lbrack {{P(r)} > \gamma} \rbrack}{\sum\limits_{i = 1}^{m}\;{{Prob}\lbrack {{P_{i}( d_{i} )} > \gamma} \rbrack}}} & (5)\end{matrix}$Wherein:

-   -   C/I is a carrier to noise ratio;    -   P(r) is a desired transmit power;    -   P_(i)(d_(i)) is the interference power with a power-control        scheme applied;    -   r is the zone radius of the mobile station;    -   d_(i) is the distance from the mobile station to the i-th code        reuse antenna; and    -   m is the total number of code reuse zones in the cell.

When the ratio of probability of C/I is smaller than a certaininterference threshold, the code reuse is applied to stationary mobilestations for which a channel allocation is requested. Thereby, viewerorthogonal codes, or radio channels otherwise-defined, are used in thecell when many mobile stations are stationary and co-channelinterferences are low. Also, more available orthogonal codes can beassigned to mobile stations that request high speed data services andmobile stations that might be entering the cell from adjacent cells thatmight request early channel reservation to assure good quality ofservices.

FIG. 2 illustrates a representation, shown generally at 58, of anadaptive selection mechanism by which selected ones of the zone antennas22 are selectively connected to receive reverse-link signals or totransmit forward-link signals. A zone selector function 62 located, forinstance, at the base transceiver station 16, selects which zone antennaat which to transduce forward-link signals for communication on aforward-link channel to the mobile station. The zone selector alsoselects which zone antennas are to be utilized to transduce reverse-linksignals transmitted by the mobile station to the network part of thecommunication system. As noted above, a single antenna transducer isutilized to transduce forward-link signals while a group of antennatransducers are utilized to detect reverse-link signals pursuant to amacro diversity scheme.

Selections made by the selector 62 are effectuated, here by a switchelement 64, that is functionally represented in the Figure. Forward-linksignals, s(t), generated on the line 66, are applied to the switchelement. On the forward-link, the switch element forms a single-pole,multiple throw element having a pole 68 for connecting the line 66 to aselected one of the zone antennas or an antenna transducer of the basetransceiver station. And, for the reverse link, the switch element formsa multiple-pole, multiple throw element, here utilizing both the pole 68and at least one additional pole 72, to connect at least two of the zoneantennas, or base transceiver station antenna, to the line 66, to causethe generation of a receive signal, r(t), thereon.

FIG. 3 illustrates a method flow diagram, shown generally at 72,representative of operation of the apparatus 26 during operation of anembodiment of the present invention. Through operation of the method,here a spreading code, is allocated for communications with a mobilestation. The code allocation is made pursuant to a reuse scheme if themobile station is determined likely to be stationary and is auniquely-assigned code if the mobile station is determined likely to bemoving at a speeding in excess of a selected threshold.

First, and as indicated by the block 74, the identification of themobile station is recorded. The identity of the mobile station isrecorded, for instance, when the mobile station is in the paging idlemode as well as the traffic mode. And, as indicated by the block 76, thezone 18 in which the mobile station is positioned and a flag associatedtherewith is set to a zero value. Such values are amongst the indiciastored at the mobile station moving behavior indicia database 42. Thestorage method by which to store the indicia is formed of, for instance,an information-theoretic framework. By building and maintaining adictionary of the pack updates of the individual mobile station, or theuser associated with the mobile station, location uncertainty andentropy algorithms can be utilized to learn the moving behavior of themobile station and characteristic profiles of the mobile station. Whenan incoming or outgoing call is requested to be terminated ororiginated, at the mobile station, operation of the apparatus 26 facesthe probability of the moving behavior of the mobile station todetermine whether the mobile station is stationary during the time ofthe request and a subsequent window thereafter. The request for thetraffic channel is indicated by the block 78.

A determination is made, as indicated by the decision block 82, as towhether the mobile station is stationary, based upon analysis of themoving behavior indicia. If the mobile station is determined to bestationary, the true, T, branch is taken to the block 84. Code reuse isutilized. Here, a look-up table is accessed to assign a reuse code.

FIG. 4 illustrates an exemplary look-up table, shown generally at 86that is accessed to determine what code to be allocated to thestationary, or slowly moving, mobile station. The alphabetic identifiersused in FIGS. 1 and 2 are again utilized in the table. The zones A–J arelisted in the column 88 of the table. And, the rows 92, indexed togetherwith the zones in successive columns 94 identify biological value of 0or 1 whether the code of that zone can be reused. If the mobile code canbe used, the code is identified as 1 in the table. For instance, zone“A” can only select a reuse code from the zone set of [G, H, I, J]. Ifthe mobile station is determined to be stationary, then the code reusemethod is applied. However, when the mobile station has already appliedthe reuse code in the cell, and the base station controller experiencesthat the mobile station is leaving the dedicated zone or that the mobilestation has started to move at a speed in excess of the selectedthreshold, the mobile station is switched to a new orthogonal code thatis not being used in the cell and shall keep using the newly-assignedcode to the end of the communication session. This type of situation isstatistically rare as the network is able to maintain a good record ofknowledge to predict the moving behavior of the mobile station. Also, ifthe mobile station is determined to be moving at a speeding in excess ofthe selected threshold, then the code reuse algorithm is not applied tothe call, even if the mobile station becomes stationary during thecommunication session. In this manner, the burden of the core network toswitch back and forth between a new code and a reuse code, isalleviated.

Referring back again to FIG. 3, pursuant to the code allocation, adetermination is made at the decision block 102 whether the flag is setto a logical one value. If not, the F branch is taken to the decisionblock 104 and a determination is made as to whether the zone in whichthe mobile station is positioned has changed and the flag is set to alogical 1 value. If the zone has not changed, the F branch is taken tothe decision block 106. At the decision block 106, a determination ismade as to whether the call has ended. If the call has ended, the Tbranch is taken to the end block 108. If the call has not ended, the Fbranch is taken back to the decision block 102.

Also, if the determination made at the decision block 102 is that theflag is of a logical 1 value, the T branch is taken to the decisionblock 106. If the mobile station is determined not to be stationary atthe decision block 82, the F branch is taken to the block 112 and thecode selected to be allocated to the mobile station is not otherwiseused in the cell 14. Also, the T branch from the decision block 104extends to the block 112.

FIG. 5 illustrates, in greater detail, the operations performed at thedecision block 82 in the determination by the apparatus 26 of whetherthe mobile station is stationary, i.e., moving at a speed less than aselected threshold. First, and as indicated by the block 116, theindicia associated with the moving behavior of the mobile station isstored at the database 42 (shown in FIG. 1) at the home locationregister of the mobile station.

Then, and as indicated by the decision block 118, a determination ismade whether the mobile station has previously been located in the samezone in a previous time interval. If so, the T branch is taken to thedecision block 122 and a determination is made whether the mobilestation shall likely remain in the same zone in a succeeding timewindow. If so, the T branch is taken to the block 84 (shown in FIG. 3).

If, instead, at the decision block 118, a determination is made that themobile station has not previously been located in the same zone, the Fbranch is taken to the block 112 (shown in FIG. 3). Also, if thedetermination made at the decision block 122 is that the mobile stationshall not likely remain in the same zone for a selected time window, theF branch is also taken to the block 112.

As an example, if the mobile station is in the same zone for aseveral-minute period, or any other appropriate time period, adetermination can be made that the mobile station is stationary at thedetermination time. After passing this first inquiry, the apparatus 26then makes a subsequent inquiry to determine the possibility that themobile station shall remain in the same zone for a succeeding timeinterval. Such determinations are made based on the values of theindicia stored at the database through analysis of the values of theindicia, the determiner 46 (shown in FIG. 1) determines the probabilityof the behavior of the mobile station in a succeeding time window. Forinstance, if the moving history of the mobile station indicates a 99%probability that the mobile station shall not be moving in a succeedingfive-minute period, then a determination can be made that the mobilestation shall likely be stationary during such succeeding 5-minuteinterval. If such a determination is made, a reused co-channel isassigned to the mobile station.

The relationship between a dedicated zone and possible code reuse zonescan be pre-processed from field measurements or simulations. A look-uptable, such as the table 86 shown in FIG. 4 can be built as code reusesets in a cell. For example, again with respect to the table 86, if themobile station is stationary in zone A and needs a traffic channel forcommunications pursuant to a communication session, the network shallselect reused code from only the zone set equals [E, F, G, H, I, J]. Thecriteria is to find the least-commonly reused code in the zone set tominimize channel interference. If there is no reused code in the zoneset, the stationary mobile station in the zone A shall select the reusedcode from the most-distance zone, i.e., select the reuse code from thezone G due to reduced channel interference levels.

And, referring back to FIG. 1, the base transceiver station 16 forms amaster base station that has the capability to serve the entire coveragearea of the cell 14. The zone set of a set equals [A, B, C, D, E, F, G,H, I, J] forms a subset of the transmission zones within the cell 14.The transceivers in all of the zones are synchronized with the main basetransceiver station 16. The zone transceivers form dual-dipole antennas22, (for micro-diversity), and are mounted, for instance, in an actualimplementation, in any appropriate location, such as at the tops ofstreet-light poles. These zone transceivers are located, for instance,close to boundary regions defining the cell. Directional antennas canalso be utilized, if needed, further to reduce interference caused bytransmissions in adjacent zones.

Exemplary transmission and receiving mechanisms are described. A mobilestation 12 shown in FIG. 1 is positioned within the zone A region. Ifthe mobile station initializes a call, a base station controller forminga part of the access network 28 of the communication system, uses asignal-strength selective method to examine the received signals fromall of the zones and a base transceiver station 16. In this situation,zone A shall receive the strongest mean RSS (receiver signal strength)transmitted by the mobile station 12, greater than the signal strengthsof signals received by other zones and the base transceiver station.Thus, the base station controller shall switch the transmitting antenna22 to the zone A only.

The distance between the mobile station 12 and the zone antenna 22 ofthe zone A is relatively small, and the signal strength required ofsignals transmitted between forward and reverse-lengths are alsorelatively weak due to the short distance required of the transmissions.The transmission interference caused by such transmissions to otherusers in the same cell is reduced. And, interference from other users isalso relatively reduced toward the same reason.

The communication system 10 includes a deployment of a master basetransceiver station 16 and a subset of transceivers defining the zoneantennas 22 at each zone 18, synchronized with the main base transceiverstation transmissions. The synchronization is effectuated using, forinstance, cable lines for wireless microwave point-to-point links. Apower control mechanism is used at all the zones to maintain a receivesignal quality. Orthogonal codes for the traffic channel are reused ifthe mobile stations are stationary and reused codes have no channelinterference between one another. Thereby, improved communications inthe communication system are possible.

The previous descriptions are of preferred examples for implementing theinvention, and the scope of the invention should not necessarily belimited by this description. The scope of the present invention isdefined by the following claims:

1. Apparatus for selectably assigning a channel for communicationsbetween a first network station and a mobile station positioned within acell defined by the first network station, the cell divided by the firstnetwork station into a first zone and at least a second zone,comprising: a position and movement determiner adapted to receiveindicia associated with positioning and movement of the mobile station,the position and movement determiner configured to determine a positionof the mobile station and a statistical indication of a speed, if any,at which the mobile station is moving; and a channel allocator adaptedto receive an indication of a determination made by the position andmovement determiner, the channel allocator configured to assign thechannel for the communications between the first network station and themobile station, channel assignation made by the channel allocatorresponsive, at least in part, to the position and the statisticalindication of the speed of the mobile stations, wherein the position andmovement determiner further determines whether the statisticalindication of the speed at which the mobile station is moving is greaterthan a selected threshold, the channel assignation made by the channelallocator being responsive, in part, to the statistical indication ofthe speed of the mobile station comprises assignation made responsive todeterminations made by the position and movement determiner of whetherthe statistical indication of the speed of the mobile station is greaterthan the selected threshold, and wherein the channel assignation made bythe channel allocator is made for the at least one of the first zone andthe second zone, the channel assignation being made pursuant to achannel reuse scheme when the statistical indication of the speed of themobile station is determined to be less than the selected threshold. 2.The apparatus of claim 1, wherein the channel assignation made by thechannel allocator is for a uniquely-assigned channel, throughout allzones of the cell, when the statistical indication of the speed of themobile station is determined to be greater than the selected threshold.3. The apparatus of claim 1, wherein the radio communication systemoperates pursuant to a code-division, multi-access (CDMA) scheme andwherein the channel assignation made by the channel allocator comprisesa code assignation.
 4. The apparatus of claim 1 further comprising anindicia database coupled to the position and movement determiner, theindicia database for maintaining a positioning and movement history ofthe mobile station and wherein the indicia to which the position andmovement determiner is adapted to receive is originated at the indiciadatabase.
 5. The apparatus of claim 4 wherein the statistical indicationof the speed at which the mobile station is moving is determinedresponsive to the movement history of the mobile station.
 6. Theapparatus of claim 4 wherein the radio communication system comprises acellular communication system having a location register associated withthe mobile station, and wherein the indicia database is embodied at thelocation register.
 7. The apparatus of claim 1 wherein the statisticalindication of the speed of the mobile station determined by the positionand movement determiner comprises a probability that the mobile stationis moving at a selected speed.
 8. The apparatus of claim 1 wherein thefirst zone and the at least the second zone into which the cell isdivided comprises a plurality of zones, a zone of the plurality at whichthe mobile station is positioned forming an active zone, zonespositioned within a selected proximity to the active zone formingproximate zones, and the zones positioned beyond the selected proximityforming nonproximity zones and wherein the position determined by theposition and movement determiner comprises an indication of the activezone at which the mobile station is positioned.
 9. The apparatus ofclaim 8 wherein the channel assignation made by the channel allocator isselectably further responsive to which ones of the plurality of zonesfrom the active and proximate zones, respectively, and which zones fromnonproximate zones.
 10. The apparatus of claim 9 wherein the channelassignation made by the channel assignor is made pursuant to a channelreuse scheme when the mobile station is determined to be moving at aspeed less than a selected threshold, the channel assigned pursuant tothe channel assignation selected pursuant to the channel reuse schedulefrom channels assigned for use at the nonproximate zones.
 11. Theapparatus of claim 10 wherein each zone of the plurality of zones isdefined by a transmit/receive antenna, downlink transmission made ateach transmit antenna, generated in synchronization, uplink transmissiondetected pursuant to a macro diversity scheme, and wherein determinationmade by the position and movement determiner are made responsive tomacro diversity detections made at the transmit/receive antenna of theuplink transmissions.
 12. A method for assigning a channel forcommunications between a first network station and mobile stationpositioned within a cell defined by the first network station, the celldivided into a first zone and at least a second zone, comprising:determining positioning of, and a statistical indication of a speed, ifany, at which the mobile station is moving; and selectably assigning thechannel for the communications between the mobile station and the firstnetwork station responsive, at lest in part, to the position andstatistical indication of the speed of the mobile station, wherein theoperation of determining comprises determining whether the statisticalindication of the speed indicates the mobile station to be moving atgreater than a selected threshold, and wherein the channel selectablyassigned during the operation of assigning is assigned pursuant to achannel reuse scheme when the mobile station is determined, during theoperation of determining, to be moving at less than the selectedthreshold.
 13. Apparatus for selectably assigning a channel forcommunications between a first network station and a mobile stationpositioned within a cell defined by the first network station, the celldivided by the first network station into a first zone and at least asecond zone, comprising: a position and movement determiner adapted toreceive indicia associated with positioning and movement of the mobilestation, the position and movement determiner configured to determine aposition of the mobile station and a statistical indication of a speed,if any, at which the mobile station is moving; and a channel allocatoradapted to receive an indication of a determination made by the positionand movement determiner, the channel allocator configured to assign thechannel for the communications between the first network station and themobile station, channel assignation made by the channel allocatorresponsive, at least in part, to the position and the statisticalindication of the speed of the mobile station, wherein the position andmovement determiner further determines whether the statisticalindication of the speed at which the mobile station is moving is greaterthan a selected threshold, the channel assignation made by the channelallocator being responsive, in part, to the statistical indication ofthe speed of the mobile station comprises assignation made responsive todeterminations made by the position and movement determiner of whetherthe statistical indication of the speed of the mobile station is greaterthan the selected threshold, and wherein the channel assignation made bythe channel allocator is for a uniquely-assigned channel, throughout allzones of the cell, when the statistical indication of the speed of themobile station is determined to be greater than the selected threshold.14. Apparatus for selectably assigning a channel for communicationsbetween a first network station and a mobile station positioned within acell defined by the first network station, the cell divided by the firstnetwork station into a first zone and at least a second zone,comprising: a position and movement determiner adapted to receiveindicia associated with positioning and movement of the mobile station,the position and movement determiner configured to determine a positionof the mobile station and a statistical indication of a speed, if any,at which the mobile station is moving; a channel allocator adapted toreceive an indication of a determination made by the position andmovement determiner, the channel allocator configured to assign thechannel for the communications between the first network station and themobile station, channel assignation made by the channel allocatorresponsive, at least in part, to the position and the statisticalindication of the speed of the mobile station; an indicia databasecoupled to the position and movement determiner, the indicia databasemaintaining a positioning and movement history of the mobile station,wherein the indicia to which the position and movement determiner isadapted to receive is originated at the indicia database, and whereinthe statistical indication of the speed at which the mobile station ismoving is determined responsive to the movement history of the mobilestation.
 15. The apparatus of claim 14 wherein the position and movementdeterminer further determines whether the statistical indication of thespeed at which the mobile station is moving is greater than a selectedthreshold.
 16. The apparatus of claim 15 wherein the channel assignationmade by the channel allocator is responsive, in part, to the statisticalindication of the speed of the mobile station comprises assignation maderesponsive to determinations made by the position and movementdeterminer of whether the statistical indication of the speed of themobile station is greater than the selected threshold.
 17. The apparatusof claim 14 wherein the radio communication system comprises a cellularcommunication system having a location register associated with themobile station, and wherein the indicia database is embodied at thelocation register.
 18. Apparatus for selectably assigning a channel forcommunications between a first network station and a mobile stationpositioned within a cell defined by the first network station, the celldivided by the first network station into a first zone and at least asecond zone, comprising: a position and movement determiner adapted toreceive indicia associated with positioning and movement of the mobilestation, the position and movement determiner configured to determine aposition of the mobile station and a statistical indication of a speed,if any, at which the mobile station is moving; and a channel allocatoradapted to receive an indication of a determination made by the positionand movement determiner, the channel allocator configured to assign thechannel for the communications between the first network station and themobile station, channel assignation made by the channel allocatorresponsive, at least in part, to the position and the statisticalindication of the speed of the mobile station, wherein the first zoneand the at least the second zone into which the cell is dividedcomprises a plurality of zones, a zone of the plurality at which themobile station is positioned forming an active zone, zones positionedwithin a selected proximity to the active zone forming proximate zones,and the zones positioned beyond the selected proximity formingnonproximity zones and wherein the position determined by the positionand movement determiner comprises an indication of the active zone atwhich the mobile station is positioned.
 19. The apparatus of claim 18wherein the channel assignation made by the channel allocator isselectably further responsive to which ones of the plurality of zonesfrom the active and proximate zones, respectively, and which zones fromnonproximate zones.
 20. The apparatus of claim 19 wherein the channelassignation made by the channel assignor is made pursuant to a channelreuse scheme when the mobile station is determined to be moving at aspeed less than a selected threshold, the channel assigned pursuant tothe channel assignation selected pursuant to the channel reuse schedulefrom channels assigned for use at the nonproximate zones.
 21. Theapparatus of claim 20, wherein each zone of the plurality of zones isdefined by a transmit/receive antenna, downlink transmission made ateach transmit antenna, generated in synchronization, uplink transmissiondetected pursuant to a macro diversity scheme, and wherein determinationmade by the position and movement determiner are made responsive tomacro diversity detections made at the transmit/receive antenna of theuplink transmissions.
 22. A method for assigning a channel forcommunications between a first network station and mobile stationpositioned within a cell defined by the first network station, the celldivided into a first zone and at least a second zone, the methodcomprising the operations of: determining positioning of, and astatistical indication of a speed, if any, at which the mobile stationis moving; and selectably assigning the channel for the communicationsbetween the mobile station and the first network station responsive, atlest in part, to the position and statistical indication of the speed ofthe mobile station, wherein the operation of determining comprisesdetermining whether the statistical indication of the speed indicatesthe mobile station to be moving at greater than a selected threshold,wherein the channel selectably assigned during the operation ofassigning comprises a uniquely-assigned channel throughout the cell whenthe mobile station is determined, during the operation of determining,to be greater than the selected threshold.
 23. A method for assigning achannel for communications between a first network station and mobilestation positioned within a cell defined by the first network station,the cell divided into a first zone and at least a second zone, themethod comprising the operations of: determining positioning of, and astatistical indication of a speed, if any, at which the mobile stationis moving; and selectably assigning the channel for the communicationsbetween the mobile station and the first network station responsive, atlest in part, to the position and statistical indication of the speed ofthe mobile station, wherein the operation of determining comprisesdetermining whether the statistical indication of the speed indicatesthe mobile station to be moving at greater than a selected threshold,and wherein determinations made during the operation of determining aremade responsive to values maintained at a positioning and movementhistory database.
 24. The method of claim 23, wherein the operation ofdetermining further comprises determining whether the statisticalindication of the speed indicates the mobile station to be moving atgreater than a selected threshold.
 25. The method of claim 24 whereinthe channel selectably assigned during the operation of assigningcomprises a uniquely-assigned channel throughout the cell when themobile station is determined, during the operation of determining, to begreater than the selected threshold.
 26. The method of claim 24 furthercomprising the preliminary operation of maintaining a positioning andmovement history database and wherein determinations made during theoperation of determining are made responsive to values maintained at thedatabase.
 27. The method of claim 26 wherein values maintained at thepositioning and movement history database are provided thereto atselected intervals by the mobile station.